Biology 1001A Lecture Notes - Lecture 10: Pyrimidine Dimer, Enol, Thymine
4 Dec 2015
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Document Summary
Mutation: change in double stranded sequence: mismatch is not a mutation; starts with damage which is then turned is not a mutation. Uv radiation causes thymine dimers that distort the helix: photon of uv light has to be the right amount of energy, thymine dimer is a typical damage caused by uv exposure. Distort helix distortion is detectable and repairable by enzyme known as phtolyase or exicsion. Uses a photon of visible light in blue range to revers damage breaks covalent bonds between thymines restoring them to original form: dimers can be repaired by both ways in, humans use exisison to repair dimers. Spontaneous tautomeric shifts change base pairing partners : creates isomer of thyming, thymine relatively stable however spends vast majority of. When it switches to enol goes to wrong base during its time in keto form sometimes switches to enol.
